Re: Re: patch submission: truncate trailing nulls from heap rows to reduce the size of the null bitmap [Review]
Simon Riggs <simon@2ndquadrant.com>
From: Simon Riggs <simon@2ndQuadrant.com>
To: Amit Kapila <amit.kapila@huawei.com>
Cc: Kevin Grittner <kgrittn@mail.com>, robertmhaas@gmail.com, josh@agliodbs.com, pgsql-hackers@postgresql.org
Date: 2013-01-09T12:14:34Z
Lists: pgsql-hackers
On 9 January 2013 12:06, Amit Kapila <amit.kapila@huawei.com> wrote: > On Wednesday, January 09, 2013 4:52 PM Simon Riggs wrote: >> On 24 December 2012 16:57, Amit Kapila <amit.kapila@huawei.com> wrote: >> >> > Performance: Average of 3 runs of pgbench in tps >> > 9.3devel | with trailing null patch >> > ----------+-------------------------- >> > 578.9872 | 573.4980 >> >> On balance, it would seem optimizing for this special case would >> affect everybody negatively; not much, but enough. Which means we >> should rekect this patch. >> >> Do you have a reason why a different view might be taken? > > I have tried to dig why this gap is coming. I have observed that there is > very less change in normal path. > I wanted to give it some more time to exactly find if something can be done > to avoid performance dip in normal execution. > > Right now I am busy in certain other work. But definitely in coming week or > so, I shall spare time to work on it again. Perhaps. Not every idea produces useful outcomes. Even after your excellent research, it appears we haven't made this work yet. It's a shame. Should we invest more time? It's considered rude to advise others how to spend their time, but let me say this: we simply don't have enough time to do everything and we need to be selective, prioritising our time on to the things that look to give the best benefit. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
Commits
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Don't assume that a tuple's header size is unchanged during toasting.
- 039680affb1b 9.2.0 cited